High-resistance iron alloy.



a r m WILLIS R. WHITNEY; OF SGH'ENEGTADY, NEW YORK, ASSIGNOR TQ GENERAL ELECTRIC GOMPANY, A. GQRPORATION OF NEW YORK.

HIGH-RESISTANCE men ALLOY- H No Drawing.

To all whom it may concern.- 7

Be it known that I, WILLIS R. WHITNEY,

-a citizen of the United States, residingat Schenectady, in the county of Schenectady and State of New York, have invented certain new anduseful Improvements in High- ResistanceIron Alloys, of which the following is a specification.

My invention comprises an alloy of iron and boron, which may be termed a boronsteel, possessing electrical properties especially adapting it" for use in electrical apparatus, such as transformer plates.

It is well-known in the electrical art when iron is traversed by a varying magnetic field there occur certain losses of energy, which reappear as heat. These losses, known as core losses l, are due to eddy, or Foucault, currents and to hysteresis effects.

Even when the iron cores are laminated to suppress the eddy currents as far as possible, the core loss throu h eddy currents and hysteresis is considera 1e, and increases in degree during the-use of the apparatus. It is, of course, most desirable to reduce this loss to the lowest possible limit. Iron, to be used for magnetic purposes, must not only. .be strong and of high magnetic permeabil ity, but must be of such quality as to give Such iron should a minimum core loss. have a h1 h electrical reslstance, at the same time retaimng the desirable mechanical and electrical properties before mentioned.

I have found that the addition of the elements boron or beryllium increases the resistivity of iron to a high degree, at the same time improving its mechanical properties,"making a valuable alloy for the abovementioned purposes.

According to my belief, the resistivity of iron is increased by the presence ofalloying elements, to a degree inversely ',t0 their atomic weights, because ofthe increased number of molecules furnished by an element'of low atomic weight per unit weight of alloy. In other'words, a given Specification bf Letters Patent. v

Patented MEL ll. i5, 93m.

Application filed January 7, 1908. Serial No. 409,676.

Weight-of alloy, containing given percent-- ages of iron and an alloying-element, will have a higher resistanceifthe atomic weight of the alloying element is low, as a'given percentage of the element introduces a relatlvely greater number of molecules than the same percentage of an element of'higher atomic eight.

The novel features of my invention are pointed out in the appended claims.

In making my high resistance alloy, I melt a mixture of commercially pure steel and a suitable ortion of ferro-boron in afire-clay cruc ble as commonly used in the crucible steel process. Ferro-boron is an alloy or mixture of iron and boron con tainlng a relatively high percentage of boron, for example, as high as 30 per cent. boron. Ferro-boron is a well-known product and may be purchased in the market. The proportion of boron in the high-resistance alloy may Vary. from about .2 per cent. to 5 per cent. boron, but for most purposes c1113 lower limit of boron content is prefera e. ished product mayreadily be controlled by The percentage of boron in the finanalyzing the ferro-boron and calculating o the amount of ferro-boron to be added necessary to give the desired. percentage in the finished product. The steel should preferably be as free as possible from sulfur, phosphorus, or other ingredients. After a thorough mingling and alloying of the iron and boron, or beryllium, the molten mass is cast into ingots and subsequently rolled into desired form by any well-known means.

The melting, casting and mechanical treat-- ment of the steel being similar to that given any crucible ste'el, is so well-known as to need no description.

WhatI claim as new and desire to secure by Letters Patent of the United States, is 1. A new article of manufacture for use in electrical apparatus, consisting of sheet steel containing boron in amounts varying from .2 per cent.to 5 per cent.

2. A; high resistance alloy 'fcrj' electrical" of iron containing .2

purposes, consisting percent. to 5 per cent. of boron.

.3; A magneticmateria1 for-electrical ap-.

5 paratus consisting of iron alloyed with boron, said mater al being characterized by high electrical resistance.

4. A magnetic'material'for electrical ap-- parit'ns consisting of iron alloyed with an 

